Rotational echo 14N/13C/1H triple resonance solid‐state nuclear magnetic resonance: A probe of 13C–14N internuclear distances

摘要: A novel triple resonance magic angle spinning (MAS) NMR experiment is reported that can be used to probe carbon–nitrogen interatomic distances in polycrystalline and amorphous solids, without the need for 15N isotopic labeling. Theory presented an S=1 nucleus under conditions of MAS a spin‐locking radio frequency (r.f.) field. An off‐resonance r.f. field only effective periods during rotor cycle where it same order magnitude as first quadrupolar splitting Q. This occurs when Q changes sign (the zero crossing) passages between Zeeman levels result. Numerical calculations are determine adiabatic passages. passage results greatest change density matrix, inverting magnetization creating order; faster passages, caused by or larger quadrupole coupling constant (e2qQ/h), result loss some non‐spin‐locked coherences. Applying off‐...